Continuation of a very important investigation sharply focused on the isolation, characterization and structural elucidation of new and potentially useful cancer chemotherapeutic drugs from marine animals has been proposed. Approval would allow continued isolation and characterization of novel anticancer substances from confirmed active extracts of marine invertebrates, and marine vertebrates. Maximum effort would be devoted to marine animal species yielding extracts with outstanding confirmed level activity (T/C greater than 150) in the National Cancer Institute's murine P388 lymphocytic leukemia system. As each problem is solved (or placed in a lower priority due to decreasing or lost activity during fractionation guided by bioassay) it would be replaced by another (of high priority) from a current collection of nearly 400 marine animal species giving extracts with a confirmed level of activity. The lower animals represent an exceedingly productive source of new cancer chemotherapeutic drugs and all effort will be directed at making such new substances available to the Division of Cancer Treatment, National Cancer Institute.